Air bags of the general type of this invention may be seen in U.S. Pat. Nos. 4,148,503, 4,183,550, 4,334,699, and 4,852,907 and Japanese laid open patent application No. 63-199149 dated Aug. 17, 1988.
As shown in FIG. 12, a conventional air bag device MO comprises a air bag 1, an inflater 2, a mounting plate 4, a retaining plate 5 and a pad 7.
An annular flange portion 3 is formed around the inflater 2 that supplies gas into the air bag 1 in case of an accident. The mounting plate 4 is disposed on the annular flange portion 3. The annular retaining plate 5 is disposed on the mounting plate 4. An underside 1a of the air bag 1 is disposed between the mounting plate 4 and the annular retaining plate 5. The annular retaining plate 5 is firmly fixed to the underside of the air bag 1 by a bolt 5a. The bolt 5a protrudes to the underside of the flange portion 3 from the upper surface of the mounting plate 4. A nut 6 is screwed to the bolt 5a. Thus, the inflater 2, the retaining plate 5 and the air bag 1 are mounted to the mounting plate 4. The pad 7 covers the air bag 1 and is also held by the mounting plate 4.
When the air bag 1 is expanded suddenly by gas that is supplied from the inflater 2, the air bag 1 is under much stress, tending to pull the underside 1a out from between the retainers 4 and 5. Therefore, the underside 1a of the air bag 1 is held by eight to twelve bolts 5a or rivets, causing a large number of manufacturing steps to be needed.
An object of the present invention is to provide an air bag device which significantly reduces the number of manufacturing steps.